Novel influenza A (H1N1) is a new flu virus of swine origin that was first detected in Mexico and the United States in March and April, 2009. The first novel H1N1 patient in the United States was confirmed by laboratory testing at CDC on April 15, 2009. The second patient was confirmed on April 17, 2009. It was quickly determined that the virus was spreading from person-to-person. On April 22, CDC activated its Emergency Operations Center to better coordinate the public health response. On April 26, 2009, the United States Government declared a public health emergency.

It’s thought that novel influenza A (H1N1) flu spreads in the same way that regular seasonal influenza viruses spread; mainly through the coughs and sneezes of people who are sick with the virus.

Since the outbreak began in the United States, an increasing number of U.S. states have reported cases of novel H1N1 influenza with associated hospitalizations and deaths. By June 3, 2009, all 50 states in the United States and the District of Columbia and Puerto Rico were reporting cases of novel H1N1 infection. While nationwide U.S. influenza surveillance systems indicate that overall influenza activity is decreasing in the country at this time, novel H1N1 outbreaks are ongoing in parts of the U.S., in some cases with intense activity.

It’s uncertain at this time how serious or severe this novel H1N1 virus will be in terms of how many people infected will develop serious complications or die or how this new virus may affect the U.S. during its upcoming influenza season in the fall and winter. Because this is a new virus, most people will have little or no immunity against it, and illness may be more severe and widespread as a result. In addition, currently there is no vaccine to protect against this novel H1N1 virus. CDC anticipates that there will be more cases, more hospitalizations and more deaths associated with this new virus.

At this time, most people who have become ill with novel H1N1 in the United States have recovered without requiring medical treatment and have experienced typical flu symptoms.

CDC is continuing to watch the situation carefully, to support the public health response and to gather information about this virus and its characteristics.

http://www.cdc.gov/h1n1flu/#stay_healthy

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